Class Xth Computer Applications Chapter-1 Internet Basics

 

Internet Basics     Chapter -1

Network: - A Network is a group of connected computers to share data and information.

Internet: - Internet is a network of networks spread worldwide. It is an international network.

History of Internet: - In 1969, the Advanced Research Project Agency (ARPA) designed a network of four computers to exchange and share data. This network was called ARPANET

Tim Berners-Lee developed the WWW (World Wide Web) in 1991.

In India, Internet services started on 15th August 1995 by VSNL (Videsh Sanchar Nigam Ltd.)

Who governs the Internet?

No particular organization governs the Internet but a number of bodies are responsible

for maintaining standards.

1. ICANN(International Council For Assigned Names and Numbers)

2. IETF(Internet Engineering Task Force)

3. IAB(Internet Architecture Board)

4. IESG(Internet Engineering Steering Group)

5. W3C(World Wide Web Consortium)

Some Important Terms: -

1. Web Client: - Web Client is the computer on which user runs the Internet. It carries request to the Server and displays the result sent by the server.

2. Web Server: - Server are powerful computers which provides data and information to the client.

3. Gateway: - A gateway is a network point that acts as an entrance to another network. It connects two dissimilar networks and provides protocol conversion.

4. Backbone: - It is the central hub that controls all networks.

5. ISP (Internet Service Provider): - ISPs are the companies which provide the service of Internet. BSNL, Airtel, Idea, Vodafone, JIO etc. are some popular ISPs.

6. MODEM (Modulator Demodulator): - A Modem is a device that converts digital signal to analog signal and vice versa.

7. Bandwidth: -It refers to the rate of data transfer in case of Internet connection.

Modes of connecting a computer to the Internet-

There are two modes of connecting a computer to the Internet.

1. Wired Broadband- Dial-Up Connection, cable, Digital Subscriber Line(DSL),Fiber Optic

    i. Dial-Up Connection: -It is used in remote areas, where broadband connectivity is                 weak. Its max. speed is 56 kbps (Kilobits per second).

    ii. Cable: - This connection is used in residential areas with 512 kbps to 20 Mbps                      (Megabits per second). It is used to access Internet via the cable T.V. connection.

    iii. DSL (Digital Subscriber Line): - It is a high speed Internet service. It allows Internet             and telephone service to work over the same phone lines without disconnect either                voice or Internet connection.

    iv. Fiber Optic cable: - It converts electrical signal into light signal. It operates at high             speed and has a large capacity to data transfer.

2. Wireless Broadband: - Wi-Fi, Satellite, WiMax.

      i. Wi-Fi: - Wi-Fi stands for Wireless Fidelity. It uses radio waves to send the information         and computer captures these signals using a wireless adapter. We should always use a            security enabled Wi-Fi connection.

      ii. Wi-Fi Hotspot: - It is the Internet access point in a public place where you can access         wireless broadband using a wireless enabled device.

      iii. Satellite: - It requires a satellite dish and other devices to receive signal. It provides             high speed Internet.

      iv. WiMax: - WiMax stands for Worldwide Interoperability for Microwave Access. It             provides high speed connection up to 75 Mbps over the area of 30 miles.

Disadvantage of Internet: - There are following disadvantage of Internet.

        i. Virus

        ii. Spamming (Unwanted E-Mails)

        iii. Theft of Personal Information

        iv. Pornography

        v. Cyber Terrorism

        vi. Banking/ Credit Card related crimes.

Web Terminology

        1.HTML: - HTML stands for Hyper Text Markup Language. It is used to create web                 pages.

        2.Web Page: - It is a document written using HTML and stored on web server.

        3.Website: - A collection of related webpages is called website.

        4.Homepage: - The first page of any website is called Homepage.

        5.Web Portal: - It is a webpage which contains links to other websites. It does not                     contain information on any topic. Ex. Yahoo, iGoogle, MSN.

        6.IP Address: - It is a unique address separated by dot. It has four parts. Each part has            a number between 0 and 255. Ex. 192.168.1.61

        7. Domain Naming System (DNS):- Domain Name is a unique name given to each                 website. DNS is a system in which domain name is interpreted into IP address.                     Some popular domain name extensions are.

                        a. .com- Commercial

                        b. .gov –Governmental

                        c. .org -Organizational

                        d. .edu – educational

                        e. .mil – military

           8.Intranet: - Intranet stands for Internet Restricted Access Network. It is a network                 within an organization in which only authorized persons can Access.

           9.Extranet: - It is the expanded form of Intranet in which some services can be                        accessed by outsiders.

           10. Web Slices: - Web Slices are part of a webpage that keep us up-to-date such as                     weather forecast, sport score etc.

            11. Bandwidth Throttling: - It is a method used to limit the quantity of data                             transmitted or accepted within a specific interval of time.

Chapter-2 Internet Services

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